Introduction. It is well known the fact that untreated chronic periodontitis will increase the level of destruction of surrounding tissues, progressing from one one type to another, finishing frequently with dental extractions and following measures of tertiary prevention – prosthetic interventions or implantology, both of them being expensive. In order to finish the conservative endodontic treatment, we apply to a kind of treatment called apical resection when it is impossible or is not recommended, saving 2/3 from the root minimum.  Aim of the study. Studying the methods of conservative and surgical treatment in chronic apical periodontitis in order to ensure the future functionality of the tooth and saving its integrity. Materials and methods. The research is based on data obtained as the result of treatment apllied for 43 patients with chronic apical periodontitis, during the 2017 and 2018 years, who addressed to University Clinic Nr. 1, to private dental studio “ExpoDent”, Chisinau city, including 24 (56%) males and 19 (44%) females between 18 and 46 years.    Results. One of the priority directions of research in modern dentistry is prophylaxis, diagnosis and treatment of chronic apical periodontits. Although they have been used as a object of study for a long time, until now chronic apical periodontits is a professional problem, for which were proposed new methods and remedies in the conservative treatment. Therefore, it is important that the most advisable methods for the removal of apical and periapical pathological outbreak to be known, thus creating conditions for healing pathological processes for the full tissue restructuring, in all cases endeavoring to keep the causative tooth. In this paper we have studied the medical records of 60 patients who have been treated during 6 months by the therapeutic method-58 patients (96,4%), and conservative surgical method-2 patients (3,3%). The reference group included three patients, two among received a therapeutic treatment and one of them a surgical treatment (apical resection). In order to achieve the periapical regeneration was used the calcium hydroxide lotion ”UltraCal”, with a treatment success rate of 80%. Conservative surgical treatment should be performed only after the therapeutic one.  Conclusions. After treatment with calcium hydroxide “UltraCal”, durind 6 months, including more visits we obtained approximative 80% recovery from all patients. In some cases of chronic periodontitis with sever lesion types, those with root canal secretion is absolutely necessary association of surgical intervention.